首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   43篇
  免费   2篇
  国内免费   1篇
化学   15篇
力学   2篇
数学   21篇
物理学   8篇
  2022年   3篇
  2021年   1篇
  2020年   2篇
  2019年   1篇
  2018年   4篇
  2017年   1篇
  2016年   3篇
  2015年   2篇
  2014年   2篇
  2013年   2篇
  2012年   5篇
  2011年   2篇
  2010年   2篇
  2009年   3篇
  2007年   2篇
  2003年   2篇
  2000年   1篇
  1999年   4篇
  1994年   1篇
  1993年   2篇
  1992年   1篇
排序方式: 共有46条查询结果,搜索用时 218 毫秒
1.
Russian Journal of Organic Chemistry - A green protocol has been developed for the preparation of 2,2′-(arylmethylene)bis(3-hydroxy-5,5-dimethylcyclohex-2-en-1-ones) following the...  相似文献   
2.
New derivation results for integrands and multifunctions via the Lipschitzean approximations are obtained. Applications to multivalued differential equations on closed convex sets are presented.  相似文献   
3.
4.
Since some synthetic insecticides cause damage to human health, compounds in plants can be viable alternatives to conventional synthetic pesticides. Dittrichia viscosa L. is a perennial Mediterranean plant known to possess biological activities, including insecticidal properties. The chemical composition of an essential oil (EOD) from D. viscosa, as well as its antioxidant, antimicrobial, and insecticidal effects on the cowpea weevil (Callosobruchus maculatus) were determined. Forty-one volatile compounds were identified in EOD, which accounted for 97.5% of its constituents. Bornyl acetate (41%) was a major compound, followed by borneol (9.3%), α-amorphene (6.6%), and caryophyllene oxide (5.7%). EOD exhibited significant antioxidant activity in all tests performed, with an IC50 of 1.30 ± 0.05 mg/mL in the DPPH test and an EC50 equal to 36.0 ± 2.5 mg/mL in the FRAP assay. In the phosphor-molybdenum test, EOD results ranged from 39.81 ± 0.7 to 192.1 ± 0.8 mg AAE/g E. EOD was active on E. coli (9.5 ± 0.5 mm), S. aureus (31.0 ± 1.5 mm), C. albicans (20.4 ± 0.5 mm), and S. cerevisiae (28.0 ± 1.0 mm), with MICs ranging from 0.1 mg/mL to 3.3 mg/mL. We found that 1 µL of EOD caused 97.5 ± 5.0% insect mortality after 96 h in the inhalation test and 60.0 ± 8.3% in the ingestion assay. The median lethal concentration (LC50) was 7.8 ± 0.3 μL EO/L, while the effective concentration in the ingestion test (LC50) was 15.0 ± 2.1 μL EO/L. We found that 20 µL of EOD caused a reduction of more than 91% of C. maculatus laid eggs.  相似文献   
5.
The purpose of this work is twofold: on the one hand, we study the second-order behaviour of a nonsmooth convex function defined over a reflexive Banach space . We establish several equivalent characterizations of the set , known as the second-order subdifferential of at relative to . On the other hand, we examine the case in which is the functional integral associated to a normal convex integrand . We extend a result of Chi Ngoc Do from the space to a possible nonreflexive Banach space . We also establish a formula for computing the second-order subdifferential .

  相似文献   

6.
7.
We prove a rgularity result, in Hölder spaces, for solutions to an elliptic problem with mixed boundary condition, namely Dirichlet on a part of the boundary and Signorini on the remaining part, in a regular or polygonal, domain of IR2 We give the behaviour of the solution near points where the boundary condition tyoe changes.

Nous montrons la Régularité jusqu'au bord, dans les espaces de Hölder des solutions d'un problème aux limites de type mêlé avec une condition de Dirichlet sur une partie de la frontière et des conditions de type Signorini sur le complémentaire, et ceci dans un ouvert plan ré gulier ou polygonal. Nous donnons en particulier le comportement de la solution au volisinge d'un point de la frontiére où la condition aux limites change de type.

Mots Clés: In´quations variationnells–conditions unilatélrales. Domains polygonaux.

Classification AMS 35 (J) 49 (A)  相似文献   
8.
9.
We consider three species system, namely prey (roach), predator (pike) and plankton. We derive persistence and extinction conditions of the populations. Using coincidence degree theory, we determine conditions for which the system has a periodic solution. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   
10.
The present paper deals with the numerical investigation of a 2D laminar fluid flow and heat transfer in a plane channel with two square blocks located at arbitrary positions. The numerical model is based on a coupling between the multiple relaxation time-lattice Boltzmann equation and the finite difference method for incompressible flow. Both the horizontal and the vertical separation distances between the two blocks are varied. Particular attention was paid to the distribution patterns of the time averaged local Nusselt number on the top and bottom walls. Results obtained from the present study show a complex flow patterns developed in the channel due to the change of the square blocks positions.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号